The case for natural refrigerants

The case for natural refrigerants

By Grace Li*

Refrigerants are a huge part of our everyday lives. 

But they’re easy to overlook.  

They quietly cycle through our homes, offices, supermarkets, and cars. They keep our bodies and consumables at safe and comfortable temperatures. They’re used to store life-saving medications  from insulin to antibiotics. And recently, they’ve played a starring role in the existence and transportation of vaccines. 

So what’s the catch? 

Unfortunately, many of today’s refrigerants have orders of magnitude greater capacities to warm the atmosphere than CO2 does. In other words, refrigerants present one of the most insidious threats to our climate. 

A 57.8-gigaton opportunity

In 2017, a team of more than 200 scholars, scientists, policymakers, business leaders, and activists compiled and ranked the “most substantive solutions to global warming.” 

They called it Project Drawdown. As part of this project, the team measured and modeled the carbon impact of more than 100 solutions through the year 2050. 

What was the number one solution?

Refrigerant management.

Of all 100 solutions  including wind turbines, food waste reduction, and tropical forest reforestation  refrigerant management came out on top. Refrigerant management represents a 57.8-gigaton opportunity of reduced CO2 equivalent over three decades. For context, in the year 2019, we emitted roughly 50 gigatons of CO2 equivalent.

The technologies needed to address refrigerant management already exist and are at our disposal. 

That said, this path won’t be a smooth one. We face obstacles within today’s policy and regulatory landscape  and an understanding gap among the general public. 

This solution seems so obvious. So how did the path to get there become so jagged? 

To uncover the fascinating and controversial history behind refrigerants, we’ll head back to 1985.

The “ozone hole”

In 1985, Nature published a paper that forever changed our understanding of the Earth’s atmosphere. 

Three researchers at the British Antarctic Survey had discovered the Antarctic “ozone hole”.

The paper identified man-made chlorofluorocarbons (CFCs) as the main culprit of ozone depletion. The discovery shocked the international community at the time  perhaps because a “hole” in the atmosphere is so alarming and easy to understand. 

In just two years, nations came together to sign the Montreal Protocol in 1987. They pledged to phase out CFCs found in refrigerants and aerosols. A later amendment to the Montreal Protocol then phased out the less damaging, but still ozone-depleting hydrochlorofluorocarbons (HCFCs). 

This success story is one of the most famous in the history of climate activism. The international community quickly rallied to address an environmental crisis. 

The result? 

A sharp decline in harmful CFCs and protections for our vulnerable ozone layer. 

Unfortunately, though, the alternative  hydrofluorocarbons (HFCs)  wasn’t much better. 

HFCs: “super climate pollutants”

Hydrofluorocarbons (HFCs) were introduced as alternatives to CFCs and HCFCs. But the release of HFCs warms the planet thousands of times more than the same amount of CO2. Most are “super climate pollutants”, and they’ve become the fastest-growing greenhouse gas emission in every country on Earth.

That’s why, in 2016, 197 countries adopted the Kigali Amendment to the Montreal Protocol. If fully implemented, this amendment would help the world avoid a 0.5-degree Celsius increase in global temperature by the end of the century.

That reduction may sound small, but it means a lot. 

It could mean the difference between 1.5 degrees and 2 degrees Celsius of warming  avoiding a significantly increased risk of extreme heat (2.6x worse), of species loss (2x to 3x worse), and of sea-ice-free summers in the Arctic (10x worse).

The Kigali Amendment is unquestionably a win for our planet. But there’s an ongoing debate over how they’ll be replaced.

The debate on refrigerants heats up

If the history of refrigerant management and regulation since the 1980s provides any learnings, it’s that we need to fully understand the environmental impacts of alternative refrigerants, from production to end of life. 

We cannot afford to repeat the cycle of replacing damaging refrigerants with only slightly less damaging ones that continue to accelerate climate change. 

With this need in mind, many organizations  including the North American Sustainable Refrigeration Council (NASRC), Environmental Coalition on Standards (ECOS), U.S. Energy Information Administration (EIA), and Greenpeace  support the use of natural refrigerants with ultra-low Global Warming Potential (GWP).

The GWP of a chemical measures how much heat it traps compared to CO2. The higher the GWP value, the more heat it traps. 

Natural refrigerants with ultra-low GWP include substances like carbon dioxide (GWP 1), ammonia (GWP 0), propane (GWP 4), and isobutane (GWP 5). Natural refrigerants can be found in nature  and throughout the past decade, they’ve gained traction in the Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R) industry, especially across Europe and Asia. 

In addition to having ultra-low GWP, there are no uncertainties around the long-term environmental impact of these refrigerants, because they’ve always been naturally occurring.

Sowing the seeds of fear 

Fear-mongering and misinformation campaigns against natural refrigerants argue that they pose severe safety risks. For example, they highlight that R-290 (propane) and R-600a (isobutane) are flammable, that R-717 (ammonia) is toxic, and that R-744 (carbon dioxide) requires higher operating pressures (and therefore higher costs).

But relatively small amounts of these chemicals are needed in hermetically sealed tubes in fridges and ACs. 

And today, we have both the tech and the understanding of safe operation needed to develop the updated standards and hardware that will enable extensive use of these refrigerants. 

Everyone else is doing it

You don’t have to go far to find natural refrigerants in action.

Let’s start with Coca Cola. 

The multinational corporation has pledged that all of its cold drink equipment will be HFC-free and will use natural refrigerants. As Marc Chasserot, the founder of Shecco, a market accelerator for natural refrigerants, points out, “They will tell you that [natural refrigerants] are dangerous, but no Coca Cola vending machine using hydrocarbons has ever blown up.” 

We can also look to Europe, where most new supermarkets now use CO2 in their fridge and freezer display cases. This development came in response to EU regulations to phase out HFCs. 

And what about ammonia? It’s been continuously used as a refrigerant since the initial practical use of vapor compression refrigeration cycles. It’s still the main refrigerant used in industrial refrigeration systems.

Manufacturers like Gree and Godrej sell hundreds of thousands of propane mini-split systems annually. And the “EcoCute” CO2 heat pump water heater has been commercialized for more than 10 years, with millions of units sold. 

The safety and technology behind HVAC/R systems using natural refrigerants has been extensively explored and de-risked via heat pumps, automotives, and commercial and domestic refrigeration. Now we need our policies, regulations, and consumer preferences to catch up and drive greater adoption of natural refrigerants  the only truly future-proof solution we have to replace HFCs. 

No time to lose

We have a small window of time in which we can still prevent the worst effects of climate change. It’s critical that we transition every sector to using the lowest-GWP refrigerants. 

Our decisions will have lasting environmental and health impacts, as these refrigerants will be locked in for the next several decades. 

So where can we find inspiration for our next steps? Existing, concrete policies. 

California, for example, has been a leader in regulating HFCs. The state aims to cut its emissions by 40 percent under 2013 levels by 2030. In 2018 California passed SB 1013, which adopted previously used federal bans on high-GWP HFCs while also allocating funding for natural refrigerant systems:

 •  Starting in 2022, new equipment with more than 50lbs (22.7kg) of refrigerant will be required to use refrigerants with a GWP of less than 150, which primarily applies to supermarkets and industrial facilities. According to the California Air Resources Board (CARB), the 150-GWP cap is expected to cut emissions per facility by more than 90 percent.

 •  On the air conditioning side, starting in 2023, new room ACs and dehumidifiers will be required to use refrigerants with a GWP of less than 750, and larger stationary ACs have until 2025 to meet this requirement.

 •  New ice rink systems will also have a 150-GWP cap (750 GWP in existing facilities).

A brighter future

These new regulations, particularly the 150-GWP caps, will help drive increased adoption of natural refrigerants. 

And we’ve already seen promising results: In 2019, more than 80 supermarkets in California employed low-GWP refrigerants. For instance, Raley’s installed an ammonia/CO2 system in a new store in Sacramento, California, anticipating the impending 150-GWP cap. 

Room air conditioning: An uphill battle 

Unfortunately for room air conditioning, we still face a regulatory uphill battle for natural refrigerant systems. (Ammonia and CO2 can only be used for commercial and industrial chillers and ACs in California.) 

Flammable refrigerants like propane (R290) are not currently allowed in California due to restrictive Underwriters Laboratories (UL) standards, despite the widespread use of these natural refrigerant air conditioning systems overseas. 

All hope is not lost

In August 2020, an International Electrotechnical Commission (IEC) working group released a proposal to update the safety standard for room AC systems, heat pumps, and dehumidifiers. This update would allow for larger amounts of flammable refrigerants like propane (R290) around the world.

According to EIA, switching “from climate-harming refrigerant gases to propane could prevent harmful emissions equal to 1,400 coal-fired power stations running for a year.”

90 percent of emissions

We also need to be thoughtful about refrigerant management at the end of life, which is when 90 percent of emissions occur.

It certainly helps if we use climate-friendly, natural refrigerants that make leaks less potent. But it’s even better if leaks don’t occur at all. 

As we phase out HFCs, we need to promote effective programs and incentives to encourage the proper disposal of refrigerants. One approach would be to introduce a complete ban on venting of refrigerants and implementing economic incentives for the recovery, recycling, and destruction of refrigerants. 

We’re in this fight together

We have a lot of work to do. We must update outdated standards, design incentives and new programs, educate the public on refrigerants, and push local and national governments around the world to act faster. 

This won’t be an easy fight to win. 

But as we’ve seen through the history of refrigerant use, phasing out one pollutant can open the door to other more harmful ones. 

Our follow-up to Kigali may be just as important as Kigali’s passage itself. And our decisions on the next class of refrigerants will determine whether or not we can finally break the cycle of warming caused by the very substances that keep us cool. 


*Grace Li is a 2021 Fellow with the Clean Energy Leadership Institute (CELI), a 501(c)(3) nonprofit dedicated to developing the next generation of clean energy leaders. She spent several years working on lowering the barriers to installing high efficiency heat pumps and decarbonizing the building heating and cooling sector with Gradient.

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